const getParam = (paramName) => { // 获取url后面的参数
  var reg = new RegExp('(^|&)' + paramName + '=([^&]*)(&|$)', 'i')
  var r = window.location.search.substr(1).match(reg)
  if (r !== null) {
    return decodeURIComponent(r[2])
  }
  return null
}
export default getParam
